The way it starts all lighthearted with SASSHHHAAA THUMPEEERR, then just ends bleakly with the same name. It also contrasts perfectly with Big Boi's cheerful verse before about getting his duck sicked. The tragedy of the story takes you completely off-guard, and seems to simultaneously turn the beat into something more sinister. I also love the bit in the middle:

"We on our back looking at the stars, talking bout what we wanna be when we grow up,
I said "what do you wanna be?" She said "alive."
It made me think for a minute, then looked in her eyes- I could have died."

first time i heard that song i listened to it about 30 times in a row because of that verse. Big Boi's best verse is probably the second one on Unhappy, though every line on Humble Mumble is pretty much perfect

I haven't listened to it in full, admittedly, for around three years; I'm far more likely to put on Aquemini now than anything, or Stankonia or Left Foot (I consider it on par with the aforementioned two, if not better) but still....it was the first hip-hop album I ever really got stuck into. well, that and College Dropout. proper running down the CD replayability in long car journeys to/from France and stuff

I can see that it's not the strongest or most cohesive of theirs but it will remain a cherished favourite for fucking years. as evolrebel said, it's an insanely good pop collection. I dunno man, it just holds a special place for me.